Charge forming method and apparatus with overspeed governor

ABSTRACT

The invention disclosed embraces a charge forming method of and apparatus embodying an instrumentally responsive to engine vibrations or disturbances brought into operation when the engine reaches a predetermined speed to automatically deliver excess fuel to the engine thereby momentarily providing a nonignitible mixture preventing overspeeding of the engine.

United States Patent 1191 Nutten et al.

Best ltvailab le'cop'y 51 May 13, 1973 CHARGE FORMING METHOD ANDAPPARATUS WITH OVERSPEED GOVERNOR Inventors: Warren D. Nutten, Grafton,Wis; Bernard C. Phillips, Toledo, Ohio Assignee: Borg-WarnerCorporation, Chicago,

Ill.

Filed: Mar. 25, 1974 Appl. No.: 454,211

Related U.S. Application Data Division of Ser. No. 302,902, Nov. 1,1972, Pat. No. 3,822,685, which is a division of Ser. No. 74,812, Sept.23, 1970, Pat. No. 3,738,608, which is a division of Ser. No, 766,580,Oct, 10, 1968,,

abandoned.

U.S. Cl. 123/127; 123/115; 123/97; 123/198 D Int. Cl. F02m 13/06 Fieldof Search 123/198 D, 127, 100, 106, 123/115,111,101,114

[56] References Cited UNITED STATES PATENTS 1,828,650 .10/1931 DuerC1181 123/106 3.521.652 7/1970 Reeks 3,601,102 8/1971 Schneider 123/119FOREIGNPATENTS 0R APPLlCATlONS 212,651 4/1965 Sweden 123/106v PrimaryExaminerChar1es J. Myhre Assistant Examiner-Ronald B. Cox Attorney,Agent, or Firm-Harry O. Ernsberger [57] ABSTRACT The invention,disclosed vembraces a charge forming method of and apparatus embodyingan instrumentally responsive to engine vibrations or disturbancesbrought into operation whenthe engine reaches a predetermined speedttoautomatically deliver excess fuel to the engine thereby momentarilyproviding a nonignitible mixture preventing overspeeding of the engine.

18 Claims, 76 Drawing Figures T ll SHEET 110F16 PMENIEU 3'882'838 SHEET1% OF 16 FZJENTED W I 3i975 73,. 882.838

sum 15 or 1 A I f 1 I CHARGE FORMING METHOD AND APPARATUS WITH OVERSPEEDGOVERNOR This is a division of application Ser. No. 302,902, filed Nov.1, 1972, now US. Pat. No. 3,822,685, which is a division of applicationSer. No. 74,812, filed Sept. 23, 1970, now US. Pat. No. 3,738,608, whichis a division of application Ser. No. 766,580, filed Oct. 10, 1968, nowabandoned.

The invention relates to a method of and apparatus for controllingdelivery of fuel and air mixture to an internal combustion engine tonormally supply a power mixture for engine operation under loadconditions and to automatically modify the mixture at predeterminedengine speed to govern the engine and prevent excessive high speed.

Internal combustion engines of the reciprocating piston type andparticularly two cycle engines are used extensively for powering tools,such as chain saws, and for other uses where the engine is periodicallysubjected to high loads. When the load is suddenly reduced or removed,overspeeding of the engine results if the throttle remains in full openposition. One of the most important uses of small two cycle engineswhere such overspeeding of the engine is encountered is that ofoperating chain saws. In the felling of trees or cutting of logs andtree limbs by the use of an engine driven chain saw, the saw issubjected to intermittent loading. When cutting a log or limb, the loadon the engine endures until the log or limb is severed. When the saw cutis completed, the saw breaks through and the engine, being momentarilyunloaded, attains an excessively high speed within a fraction of asecond after the load is removed. Overspeeding of a small engine,particularly an engine of the two cycle type, may result in severedamage to the engine for several reasons. As the lubricant for thetwo-cycle engine is contained in the liquid fuel there may beinsufficient lubrication at excessive high speed. The components of theengine subjected to excessive high speed may be broken or fractured bycentrifugal forces. As running friction is greatly increased at highengine speeds, piston or bearing seizure may ensure rendering the engineinoperable.

If the operator does not instantly reduce the speed of the engine bymanipulation of the throttle when a no load condition occurs, enginedamage is liable to ensue. Chain saw operators, in trimming limbs from afelled tree are prone to walk along the tree trunk cutting off the limbssuccessively while holding the throttle continuously in wide openposition causing severe overspeeding of the engine between the limbcutting operations, a practice which usually results in damage to theengine. Such conditions of operation greatly reduce engine life andsubject the saw manufacturer to excessive warranty claims. The samedifficulties are encountered in other uses of internal combustionengines where the engine is subjected to overspeeding under no loadconditions.

The invention embraces a method of preventing excessive high speed of aninternal combustion engine by automatically modifying the fuel and airratio of the fuel and air mixture when the engine exceeds apredetermined speed, the modification or change in fuel to air ratiobeing effected through a medium or means responsive to engine vibrationsor disturbances independently of the aspiration or reduced pressureexistent in the charge forming apparatus or carburetor providing thenormal fuel and air mixture.

Another object of the invention resides in a method of governing theoperation of an internal combustion engine, the method involving theautomatic delivery of an excess amount of liquid fuel to the enginewhenever the engine attains a predetermined speed, the delivery ofexcess fuel being controlled by a vibration responsive instrumentality.

Another object of the invention resides in a method of governing orlimiting the speed of an internal combustion engine to preventoverspeeding of the engine involving a medium responsive to enginevibration occurring at a predetermined engine speed effective tosuperimpose excess liquid fuel on the normal fuel and air mixturesupplied to an engine to effect an impaired or slow burning mixtureresulting in an instantaneous decrease in the power of the engine andhence a substantial reduction in engine speed.

Another object of the invention resides in a method of governing thespeed of an internal combustion engine involving the automatic-deliveryof an excess of liquid fuel into any region of the induction systemthrough the use of an instrumentality responsive to a predeterminedfrequency of vibration of the engine.

Another object of the invention resides in an apparatus or deviceactivated by or rendered out of phase with engine vibration ofpredetermined frequency to thereby deliver an excess of fuel into theinduction system operative to reduce the engine speed.

Still another object of the invention is the provision in the inductionsystem of an internal combustion engine of a vibration responsive valverendered effective at a predetermined frequency to admit an excess ofliquid fuel into the induction system or charge forming device tothereby reduce engine speed.

Another object of the invention is the provision of a vibrationresponsive valve associated with the induction system or charge formingapparatus for an internal combustion engine intercalated with fuelconveying passage means for delivering excess fuel to the engine at apredetermined frequency of vibration of the engine to preventoverspeeding thereof.

Further objects and advantages are within the scope v of this inventionsuch as relate to the arrangement, op-

eration and function of the related elements of the structure, tovarious details of construction and to combinations of parts, elementsper se, and to economies of manufacture of numerous other features aswill be apparent from a consideration of the specification and drawingof a form of the invention, which may be preferred, in which:

FIG. 1 is a side elevational view of a portion of a chain saw ofconventional construction illustrating the engine and a combineddiaphragm carburetor and fuel pump construction embodying a form of theinvention;

FIG. 2 is a top plan view of a combined diaphragm carburetor anddiaphragm fuel pump construction shown in FIG. 1 embodying a form of theinvention;

FIG. 3 is a side elevational view of the construction shown in FIG. 2;

FIG. 4 is an elevational view of the opposite side of the constructionshown in FIG. 2;

FIG. 5 is a view of the air inlet end of the carburetor and fuel pumpconstruction shown in FIG. 2;

FIG. 6 is a view of the mixture outlet end of the carburetor and fuelpump construction;

FIG. 7 is an enlarged longitudinal sectional view through the carburetorand fuel pump construction, the section line being taken substantiallyon the line 77 of FIG. 2;

FIG. 8 is an enlarged transverse sectional view taken substantially onthe line 88 of FIG. 7;

FIG. 9 is an enlarged fragmentary sectional view taken substantially onthe line 9--9 of FIG. 3;

FIG. 10 is an enlarged sectional view taken substantially on the line10-10 of FIG. illustrating one form of overspeed governor means embodiedin the carburetor;

FIG. 11 is an enlarged fragmentary sectional view taken substantially onthe line 1111 of FIG. 4 illustrating the overspeed governor means shownin FIG.

FIG. 12 is a detail sectional view of a modified form of overspeedgovernor instrumentality;

FIG. 13 is a detail sectional view illustrating another form ofoverspeed governor instrumentality similar to that shown in FIG. 11;

FIG. 14 is an enlarged longitudinal sectional view of a charge formingapparatus or carburetor of the floatcontrolled type embodying a form ofoverspeed governor instrumentality of the invention;

FIG. 15 is an elevational view illustrating a reciprocating-pistoninternal combustion engine of the four cycle type illustrating a form ofoverspeed governor instrumentality of the invention associatedtherewith;

FIG. 16 is a top plan view ofa portion of the carburetor or chargeforming apparatus of FIG. 15 illustrating the position of the overspeedgovernor means of the invention;

FIG. 17 is an enlarged fragmentary detail sectional view of a form ofoverspeed governor means of FIG. 15, the view being taken substantiallyon the line l7-17 of FIG. 15;

FIG. 18 is an end view of the construction shown in FIG. 17;

FIG. 19 is an elevational view of a two cycle engine associated with afloat type carburetor and embodying a form of overspeed governorinstrumentality of the invention;

FIG. 20 is an elevational view of a two cycle engine associated with adiaphragm type carburetor and embodying a form of overspeed governorinstrumentality of the invention;

FIG. 21 is a longitudinal sectional view of the diaphragm typecarburetor illustrated in FIG. 20;

FIG. 22 is an elevational view of a reciprocating piston four cycleengine equipped with a float-controlled type carburetor in combinationwith an engine-driven fuel pump and an overspeed governor means of theinvention associated with the mixture intake manifold;

FIG. 23 is a top plan view of the carburetor shown in FIG. 22 embodyingan overspeed engine governor instrumentality;

FIG. 24 is a view similar to FIG. 23 illustrating a fitting between thecarburetor and the intake manifold equipped with an overspeed governormeans of the invention;

FIG. 25 is a sectional view of a diaphragm type carburetor and fuel pumpconstruction similar to the form shown in FIG. 8 and embodying a form ofoverspeed engine governor means of the invention;

FIG. 26 is a top plan view of a diaphragm type carburetor and fuel pumpdisposed within an air filter enclosure, the arrangement embodying aform of overspeed governor of the invention;

FIG. 27 is an enlarged detail sectional view of a form of overspeedgovernor device embodied in the arrangement shown in FIG. 26;

FIG. 28 is a top plan view of a diaphragm type of charge formingapparatus or carburetor equipped with an overspeed governor means of theinvention;

FIG. 29 is a longitudinal sectional view through the carburetor, theview being taken substantially on the line 2929 of FIG. 28;

FIG. 30 is a transverse sectional view taken substantially on the line3030 of FIG. 28;

FIG. 31 is an enlarged fragmentary transverse sectional view takensubstantially on the line 31-3l of FIG. 28;

FIG. 32 is a view similar to FIG. 31 illustrating a form of capillaryseal arrangement for a main fuel delivery orifice associated with theoverspeed governor device of the invention;

FIG. 33 is a top plan view of a carburetor similar to FIG. 28 embodyinga modified form of overspeed governor device;

FIG. 34 is an enlarged detail sectional view taken substantially on theline 3434 of FIG. 33;

FIG. 35 is a top plan view of a charge forming apparatus similar to FIG.33 embodying a form of overspeed governor means of the invention;

FIG. 36 is an enlarged detail sectional view taken substantially on theline 3636 of FIG. 35;

FIG. 37 is a longitudinal sectional view through a carburetor similar toFIG. 10 illustrating a modified fuel channel arrangement for theoverspeed governor device;

FIG. 38 is an enlarged detail sectional view taken substantially on theline 3838 of FIG. 37;

FIG. 39 is a top plan view of a diaphragm type carburetor embodying aform of overspeed governor of the invention;

FIG. 40 is a side elevational view of the construction shown in FIG. 39;

FIG. 41 is a horizontal sectional view taken substantially on the line41-41 of FIG. 40;

FIG. 42 is an enlarged detail sectional view taken substantially on theline 42--42 of FIG. 41;

FIG. 43 is an enlarged detail sectional view taken substantially on theline 4343 of FIG. 40;

FIG. 44 is an enlarged fragmentary sectional view similar to FIG. 42illustrating a capillary seal anti-back bleed means in the main fueldelivery orifice;

FIG. 45 is an enlarged sectional view illustrating a modified form ofoverspeed governor instrumentality;

FIG. 46 is an enlarged sectional view illustrating another modificationof overspeed governor means;

FIG. 47 is an end view of the construction of FIG. 46;

FIG. 48 is an enlarged sectional view illustrating another modified formof overspeed governor means;

FIG. 49 is a bottom plan view of a carburetor with the diaphragm removedshowing the fuel chamber, the carburetor being of the general charactershown in FIGS. 39 and 40 and embodying a further modification of'overspeed governor means of the invention;

FIG. 50 is a sectional view taken substantially on the line 5050 of FIG.49 illustrating the overspeed governor means;

FIG. is an enlarged detaiied sectional view illus- V trating anothermodified form of overspeed governor means;

FIG. 52 is an end view of the construction of FIG. SI;

Fl $3 is an enlarged sectional view of a further modification ofoverspeed governor means;

FiG. is a sectional view taken substantially on the line S ll-5d of FIG.53;

Fifi. n5 is a view similar to FIG. illustrating a modified form ofoverspeed governor construction of the invention;

FIG as is a sectional view taken substantially on the line 5n5d of FIG.55;

FIG. is an enlarged detail sectional view of the over need governorconstruction shown in FIGS. 55 and FIG. is an end view of theconstruction shown in FIG. :37;

FiG. is a sectional view of a closure member for the construction shownin FIG. 57;

FIG. an is a view of the construction shown in FIG. 5'7 with a sealingmeans for sealing the adjustment in fixed position;

FIG. fit is a view similar to FIG. 57 illustrating a modified form ofseat configuration for the vibration responsive bail valve;

FIG. re is an enlarged sectional view similar to FIG. illustrating aclosure means for the adjustable member;

FIG. as is an end view of the construction shown in FiG. 52;

FIG. (1 i is an enlarged sectional view illustrating a modified form ofadjustable overspeed governor construotion;

FiG. as is an end view of the construction shown in FIG. 6-4;

FiG. an is a fragmentary sectional view of a portion of the constructionshown in FIG. 64 illustrating a sealing means for the adjustment;

FIG. s7 is an enlarged sectional view illustrating an other form ofoverspeed governor construction of the invention;

FIG. FEG. e7;

FIG. is an enlarged sectional view illustrating another form ofoverspeed governor construction;

FIG. l ft is an end view of the construction shown in FIG. as;

"" H is an enlarged sectional view similar to FIG.

is an end view of the construction shown in l "1U. h l illustrating aclosure for the housing of the overspeed governor construction;

MG. 72 is an end view of the construction shown in FIG. 7t;

FIG "3 is an enlarged longitudinal sectional view ilng another form ofoverspeed governor means; t is an end view of the constructionillustrated Flt, i

FIG

ing piston engine illustrating the relationship of the o crspeedgovernor means shown in FIG. 73 with moving components of an engine forattaining overspeed governor operation, and

Fifi, 7a is an enlarged sectional view of another modification of theoverspeed governor means of the invention.

method and the apparatus of the invention involve feeding an excess ofliquid fuel to a reciprocating piston internal combustion engine ofeither the two cycle or four cycle type through the use of a vibrationresponsive body actuated by or rendered out of phase with enginevibrations or disturbance occurring at a particular speed of the engineto cause oscillation or relative displacement of the body and therebyadmit fuel into the engine induction system in an amount ef fective toreduce the. engine speed and prevent overspeed of the engine.

The apparatus for accomplishing this method is re ferred to hereingenerally as a vibration responsive instrumentality, means or unitproviding an overspeed governor, the governing medium being responsiveto and actuated or displaced by engine vibrations when the engineattains a predetermined speed. The over speed governor method andarrangement of the invention have particular utility with iow horsepowertwo and four cycle engines and especially engines employed for poweringchain saws, lawn mowers, portable drills and the like It is found thatthe vibration responsive means or valve may be arranged to deliverliquid fuel into various regions of the induction system of an engineand the drawings illustrate various arrangements for positioning ormounting a vibration responsive body or valve whereby it is subjected toengine vibrations and is effected at a particular frequency of vibrationto be moved or oscillated by such vibration to admit excess fuel to theengine for engine governing purposes.

Referring initially to FIG. I there is illustrated a side elevationalview, partly in section, of a portion of the power driven chain sawshowing a form of charge forming apparatus or carburetor embodying theinvention associated with the engine. The arrangement shown in FIG. I isinclusive of a chain saw frame construction 10 which forms an integralpart of an engine crankcase 11 of a two cycle engine I2 on which ismounted a cylinder 1 13 having cooling fins I5. Slidable in the cylinderI4 is a conventional piston 16 having a piston pin 17 connected by aconnecting rod 18 with a crank pin 19 on a crank arm of a crankshaft 2t]journally supported in the crankcase II.

The engine illustrated is of the two cycle type, viz. wherein the fueland air mixture is admitted into the chamber provided by the crankcaseII and compressed therein upon the down stroke of the piston in, thecompressed mixture being then delivered through a suitable port into thecombustion chamber of the cylinder above the piston in the conventionalmanner. The mixture is ignited by a spark plug 22. at each revolution ofthe crankshaft.

The fuel and air combustible mixture is provided through a combined fuelpump and carburetor or charge forming apparatus 24 mounted by the enginecrankcase, the carburetor illustrated being shown in detail in FIGS. 2through if and hereinafter described.

The frame I0 is fashioned with a forwardly extending portion 34- towhich is secured an elongated plate-like member 35 providing a supportand guide means for an endless chain type saw construction 36. The sawsupport plate 35 is secured to the frame by means of bolts 37. Theforward end of the support member 35 is provided with a housing 38 whichjournally supports a roller guide 39 which is engaged by the chain saw36 in the conventional manner.

A removable housing on the opposite side of housing 42. encloses aconventional centrifugally-actuated

1. A fuel flow control construction for use with the induction system ofan internal combustion engine for delivering excess fuel from a supplyto the engine including, in combination, means providing a chamber, arelatively movable valve member in said chamber being solely responsiveto engine structural vibration transmitted through the engine frame,said valve member having a spherically curved surface region, a valveseat surface disposed to be engaged by the spherically curved surfaceregion of the valve member, said valve seat surface being configuratedto define a fuel port, spring means providing the sole force normallybiasing the valve member to port-closing position, fuel passage means incommunication with said chamber, said valve member being of a mass to bevibrated away from the valve seat surface under the influence of enginestructural vibration of a predetermined frequency to effect flow of fuelfrom the supply through said port.
 2. The combination according to claim1 wherein the valve seat surface is of frusto-conical shape.
 3. Thecombination according to claim 1 wherein the valve member biasing meansis a coil spring.
 4. The combination of claim 3 including a relativelymovable element engageable with the spring for damping movementsthereof.
 5. The combination according to claim 3 including means forregulating the biasing pressure of the coil spring.
 6. A fuel flowcontrol construction for use with the induction system of an internalcombustion engine for delivering excess fuel from a supply to the engineincluding, in combination, means providing a chamber, a relativelymovable valve member in said chamber being solely responsive to enginestructural vibration transmitted through the engine frame, said valvemember having a curved surface region, a valve seat surface disposed tobe engaged by the curved surface region of the valve member, said valveseat surface being configurated to define a fuel port, means normallybiasing the valve member to port-closing position, said valve memberbiasing means being a body of foam material, adjusting means forcontrolling the biasing pressure of the body on the valve member, andfuel passage means in communication with said chamber, said valve memberbeing of a mass to be vibrated away from the valve seat surface underthe influence of engine structural vibration of a predeterminedfrequency to effect flow of fuel from the supply through said port. 7.The combination According to claim 1 wherein the valve member biasingmeans is a plate spring.
 8. The combination according to claim 1 whereinthe valve member is a ball of metallic material.
 9. A fuel flow controlconstruction for use with the induction system of an internal combustionengine to admit excess fuel from a fuel supply to the engine including,in combination, a housing providing a chamber, means for conveying fuelfrom the supply to the chamber, a relatively movable valve body in saidchamber and having a spherically curved valve surface, said valve bodybeing solely responsive to engine structural vibration transmittedthrough the engine frame, a valve seat for the spherically curved valvesurface of the valve body, said seat being configurated to define a fueloutlet port, said port being in communication with the engine, springmeans normally biasing the valve body to port-closing position, saidspring means being the sole force biasing the valve body to portclosingposition, said valve body being of a mass to be vibrated away from thevalve seat under the influence of engine structural vibration of aparticular frequency to effect flow of fuel through said port to theengine.
 10. The combination according to claim 9 wherein the springmeans is a coil spring.
 11. The combination according to claim 9 whereinthe valve body is of spherical shape.
 12. The combination according toclaim 9 including an adjustable member in said housing for adjusting thebiasing pressure of the spring means.
 13. The combination according toclaim 12 including means for retaining the adjustable member in adjustedposition.
 14. In combination, a carburetor for an internal combustionengine having a body provided with a mixing passage and a fuel chamber,fuel passage means opening into the mixing passage for delivering fuelfrom the fuel chamber into the mixing passage for normal engineoperation, means for delivering excess fuel into the mixing passage forimpairing engine operation to limit engine speed including a bore in thecarburetor body, a housing disposed in the bore, said housing beingformed with a valve chamber, a relatively movable sphericallyshapedvalve member in said valve chamber, said valve member being solelyresponsive to engine structural vibration transmitted through the engineframe, a valve seat surface in the housing configurated to provide afuel port in communication with the mixing passage, passage means forconveying fuel from the fuel chamber into the valve chamber in thehousing, spring means normally biasing the valve member to port-closingposition, said spring means being the sole force biasing the valvemember to port-closing position, said valve member being of a massresponsive to a particular frequency of engine structural vibration,said valve member being vibrated away from its seat surface under theinfluence of the particular engine structural vibration frequency topermit flow of fuel through said port into the mixing passage.
 15. Incombination, a carburetor for an internal combustion engine having abody provided with a mixing passage and a fuel chamber, a diaphragmforming a wall of the fuel chamber, inlet valve means actuated by thediaphragm for controlling delivery of fuel from a supply into the fuelchamber, fuel passage means opening into the mixing passage fordelivering fuel from the fuel chamber into the mixing passage for normalengine operation, a bore in the carburetor body, means for deliveringexcess fuel into the mixing passage for impairing engine operationincluding a housing disposed in the bore, said housing being formed witha valve chamber, a relatively-movable spherically-shaped valve member inthe valve chamber, said valve member being solely responsive to enginestructural vibration transmitted through the engine frame, a valve seatassociated with the housing shaped to provide a fuel port, said fuelport being in communication with the mixing passage, passage means forconveying fuel from the fuel chamber in the carburetor body into thevalve chamber in the housing, and a coil spring in said housing normallybiasing the valve member to port-closing position, said coil springbeing the sole force biasing the valve member to port-closing position,said valve member being responsive to a predetermined frequency ofengine structural vibration whereby at said frequency the valve memberis moved from its seat to admit fuel through the fuel port.
 16. Thecombination according to claim 15 wherein the valve-engaging surface ofthe valve seat is of frusto-conical shape.
 17. The combination accordingto claim 15 wherein the valve seat is of nonmetallic material.
 18. Thecombination according to claim 15 wherein the valve seat is adjustablelengthwise of the housing for controlling the biasing pressure of theresilient means.